From: Kim
Hi Jessica, I was wondering if you can shed any light on my horse's problem, because the vets involved in his care are stumped! He's a 16 year old TB/WB mix. When I bought him 2 1/2 years ago he was very underweight. And it's taken a long time but his weight is finally acceptable. He gets 1 scoop of Stridor and 1/2 scoop of Senior feed twice a day and just about all the hay he can eat. There is no grass where he lives so he never gets any. He gets grass hay grown locally except in winter when it's shipped in. About 1 1/2 years ago he developed what looked like EPM symptoms. We took him to an equine vet center where a vet who specializes in equine neurology assessed him and drew blood work and did a spinal tap. She was sure he had EPM based on his presentation but both the blood test and spinal tap came back negative. She was really stumped and didn't have much to offer me except to put him on 7500IU/day of Vitamin E (without selenium). By the way, he's 16.2 hands and is very long....he's HUGE!!! She advised my local vet to draw a vit.E level on him before we started supplementing. The level came back 1.08 and I was told the normal is between 3-4. So we started the vit. E. At the same time, I was desperate to help him so I asked my vet to let me give him the EPM medicine just in case the tests somehow were wrong. My horse's hind end was so weak that the vet advised me not to ride him as he may fall down. So I stopped riding him but he seemed to get so depressed. At this point I started giving him the Vit. E and Pyrimethamine to hopefully arrest the disease process and maybe even restore his strength. I also started riding him again very lightly as a form of physical therapy. We did nothing but walk and eventually a little trotting for 4-5 mos. After 2 mos of this therapy the vet came back to see him and was amazed at the improvement. After 4 mos. we redrew a vit. E level and it was still incredibly low (1.24), but the horse (Arizona) was improving almost everyday. So he's been on Vit. E ever since and has been doing great, he regained about 80% of the strength in his hind legs over the last year and a half. Until lately..... he's been getting weak again. I spoke with my vet and he suggested I up the Vit.E (to 15,000IU/day if needed. I've increased it to 10,000IU/day and will also add Selenium as the vet says our area soil is deficient in selenium. Don't worry, I know not to give him the 10,000IU of Vit. E that comes with the selenium. Sorry for this incredibly long tale, but I have 2 questions, #1) have you ever heard of anything like this? and #2) He gets vegetable oil in his grain, do you think it's interferring with the vit. E replacement? and should I stop the oil? Thank you so much in advance if there's any advise you can give me or even for getting through this letter!!! I love this horse dearly and hope you can help me help him. Thanks, Kim
Yes, I've heard of something very much like this, most often in draught horses, occasionally in certain Warmbloods, also in light horses of many breeds. It seems to be a form of myositis, and there's a strong connection between the disease and a deficiency of vitamin E.
There is quite a lot of research that shows a connection between vitamin E deficiency and EPM, EMND, EPSM and EDM. You already know what EPM is, so I won't go into that. EDM (equine degenerative myeloencephalopathy), a disease of the spinal cord and brain stem, is one of the causes of 'wobbler syndrome' - and it too has been linked to a vitamin E deficiency.
EMND (Equine motor neuron disease) is a comparatively rare disease of the nerve cells controlling the skeletal muscles. Horses with EMND may become thin and show muscle atrophy, spend a good deal of their time lying down, tremble, and shift their weight constantly from one hind leg to the other. They may also do a lot of sweating with no apparent reason. When veterinarians take blood or tissue samples from these horses, the samples invariably show low levels of vitamin E. The cause still isn't known, but some environmental risk factors have been identified, and the main one is a combination of no grazing (in other words, no fresh green feed, which is the primary source of vitamin E) and low-quality hay. In the research with which I'm most familiar, a group of EMND horses was put on pasture for a long period (up to two years), and several of the horses were also given supplemental vitamin E. Four of the five horses in the group showed dramatic clinical improvement. In a related experiment, horses were put on a diet deficient in vitamin E for a year or more, after which most did develop EMND.
EPSM is another vitamin E- related condition. Horses with EPSM have a low tolerance for exercise - even mild exercise. They will often seem to be lame, a little or a lot, but always "off". They may find it difficult to walk backward, or to get up when they have been lying down. Sometimes there is no overt lameness, but the horse will seem thin, poorly-muscled, and apathetic - this is the horse that you turn out into a field and instead of running around, it just stands there, head low, seemingly completely without energy.
There's no one breed that gets this disease, although I'm most familiar with its manifestation in draught horses. It occurs in most of our (USA) light horse breeds, as well as in our draught horses and mules. Your vet can give you more information.
And now, back to the vitamin...
Where do horses get vitamin E?
For horses, the source of vitamin E is fresh green pasture. When a horse doesn't have access to pasture, it doesn't have access to vitamin E - unless the vitamin is added to its feed.
There is very little vitamin E added to most bagged horse feeds. What little there is can be destroyed by storage, heat, age, and sunlight - and the same is true of the vitamin E in your supplement bottles. Fresh vitamin E supplements, properly stored (in a dark bottle in a cool place), may help your horse. Old or inappropriately-stored vitamin E supplements may have no effect whatsoever.
What does vitamin E do?
We're still learning about the metabolic role of this vitamin. We know that it seems to prevent free radical damage to tissues, and that it has an effect on the oxygen available to blood and muscles. Without sufficient vitamin E, nerves and muscles cannot function properly.
Is it safe to supplement?
Vitamin E toxicity is rare. Regular blood checks and supplementation if necessary can be cheap insurance for your horse's health. If your horse is out on good green pasture most of the year, he is highly unlikely to have a vitamin E deficiency - but if he has no access to green pasture, or if he spends a great deal of time in the barn, he will probably need supplementation. Even good hay can lose a lot of its vitamin E content while it's being harvested and stored. Young horses, sick horses, horses in hard work, and old horses will probably also benefit from supplemental vitamin E. Ask your veterinarian about horses' changing needs for vitamin E - and about their changing ability to absorb the vitamin.
How much vitamin E does a horse need?
How much does an individual horse need? It depends. The research results seem to show that whereas 2,000 IU each day may be enough to prevent neurologic dysfunction, there's a much higher vitamin requirement for horses that are already suffering from one of the neuromuscular diseases. For those horses, recommended dosages are much higher, between 6,000 and 9,000 IU each day - or more, sometimes much more. Again, talk to your vet - he can tell you about the most recent research and the reported results, and discuss how this information may apply to your own horse. The amounts you are feeding are NOT at all unreasonable - this vet sounds like a very good one. ;-)
Vitamin E seems to be a reasonably useful treatment, but a much better preventive measure. What this means for horse-owners, I suppose, is that if your horses are, for whatever reason, deprived of pasture for a year or longer, you should probably have them tested for plasma vitamin E so that you can begin supplementing the vitamin if it's needed, BEFORE any disease develops.
Dietary fat and vitamin E - what's the connection?
In the last five or ten years, we've become increasingly aware of the importance of fat in the equine diet. Fat is an excellent, easily-digested source of energy, and many horses are now consuming diets that are quite high in fat. Something we may not have thought enough about is the fact that any diet high in unsaturated fat is going to increase the body's requirements for vitamin E. There's nothing wrong with feeding fat to horses, whether it's to help the digestion of an old horse or to "shine up" the coat of a show animal, but it IS important to realize that with every increase in fat there should be an increase in the animal's consumption of vitamin E.
Which vitamin E? Does it matter?
And while we're on the subject of this vitamin - let's talk for a moment about natural vitamins vs synthetic ones. For some vitamins, it doesn't matter - the natural and synthetic versions are identical, and both the natural and the synthetic versions work the same way. Unfortunately this is not true of vitamin E - the natural and synthetic versions are NOT the same. Some natural molecules are produced in two forms that are mirror images of each other, and the body is very particular about which form it accepts.
We can't synthesize an equivalent version of the vitamin E molecule - we're just not that sophisticated yet! The synthetic "d-l" version is NOT a duplicate of the natural "d" version. In the case of vitamin E molecules, only the natural version will actually "fit" the body's receptors. This is why the natural version has been shown to remain in the body longer and why it gets distributed to the tissues more effectively. The "d-l" version is going to be roughly half as effective as the "d" version - IF that.
Natural vitamin E is more biologically active than its synthetic counterpart, and may be as much as twice as bio-available. This is why many doctors and veterinarians are recommending that their patients take the natural vitamin E rather than the synthetic version.
Read your labels carefully! There's a one-letter difference between the natural and the synthetic, very easy to miss if your eyesight is poor or if you are in a hurry. The label on the natural vitamin E will begin with "d" (e.g., d-alpha-tocopherol), whereas the synthetic one will begin with "dl" (e.g., dl-alpha-tocopherol). It's easy to make a mistake.
Probably the best way to feed the supplement will be to purchase the natural vitamin E in capsules and add the vitamin to your horse's daily feed by piercing the capsules and squeezing the oil onto the horse's grain. There was a time when horseowners who wanted to feed additional vitamin E would buy gallons of wheat germ oil and add that to their horses' diets, but this isn't always successful. The oil, like any other oil, can go rancid rather quickly, at which point it is useless as well as unpalatable. It doesn't take long for the active vitamin E to disappear from wheat germ oil, and I wouldn't recommend it as a reliable source of vitamin E. Again, ask your vet - he may know of a source for small amounts of fresh wheat germ oil. Whatever kind of oil you are feeding, be sure that it is FRESH. Rancid oil, even slightly rancid oil, can really use up all of the vitamin E you're feeding the horse... under the circumstances, I'd be tempted to use small containers of cold-pressed oils.
I think that you've had good advice so far, Kim. Vitamin E is what most of the top vets I know would probably be recommending! Find a good-quality natural (d-alpha) vitamin E supplement that is NOT part of a "Vitamin E and selenium" combination. You already know how important it is to increase your horse's vitamin E without putting him at risk of selenium toxicity. Talk with your vet about finding a good source for the natural vitamin - the natural version IS expensive, but you want to do what's best for your horse, and it's quite possible that your vet may know of a source where you can buy larger capsules in bulk. The small bottles of 400IU capsules sold to humans are likely to be quite costly, but even those will do if nothing else is available to you.
Feeding good-quality, natural "d-alpha" vitamin E won't be cheap, but heaven knows that EPM meds and spinal taps aren't cheap either, and you've already shown that you were willing to go that route. With your veterinarian's help, you should be able to get a significant and helpful amount of high-quality natural vitamin E into your horse. Keep monitoring his plasma vitamin E, so that you'll be able to match any clinical changes to the changes in his blood values. Keep me posted, please - and good luck!
Jessica
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